Solar cell efficiency tables (version 37)

Abstract

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined and new entries since June 2010 are reviewed. Copyright © 2010 John Wiley & Sons, Ltd.

INTRODUCTION

Since January 1993, ‘Progress in Photovoltaics’ has published six monthly listings of the highest confirmed efficiencies for a range of photovoltaic cell and module technologies 1–3. By providing guidelines for the inclusion of results into these tables, this not only provides an authoritative summary of the current state of the art but also encourages researchers to seek independent confirmation of results and to report results on a standardised basis. In a recent version of these tables (Version 33) 2, results were updated to the new internationally accepted reference spectrum (IEC 60904–3, Ed. 2, 2008), where this was possible.

The most important criterion for inclusion of results into the tables is that they must have been measured by a recognised test centre listed elsewhere 1. A distinction is made between three different eligible areas: total area; aperture area and designated illumination area 1. ‘Active area’ efficiencies are not included. There are also certain minimum values of the area sought for the different device types (above 0.05 cm² for a concentrator cell, 1 cm² for a one-sun cell and 800 cm² for a module) 1.

Results are reported for cells and modules made from different semiconductors and for subcategories within each semiconductor grouping (e.g. crystalline, polycrystalline and thin film). From Version 36 onwards, spectral response information has been included when available in the form of a plot of the external quantum efficiency (EQE) versus wavelength, normalized to the peak measured value.

NEW RESULTS

Highest confirmed “one-sun” cell and module results are reported in Tables I and II. Any changes in the tables from those previously published 3 are set in bold type. In most cases, a literature reference is provided that describes either the result reported or a similar result. Table I summarises the best measurements for cells and submodules, while Table II shows the best results for modules. Table III contains what might be described as ‘notable exceptions’. While not conforming to the requirements to be recognized as a class record, the cells and modules in this Table have notable characteristics that will be of interest to sections of the photovoltaic community with entries based on their significance and timeliness.

Table I. Confirmed terrestrial cell and submodule efficiencies measured under the global AM1.5 spectrum (1000 W/m2) at 25°C (IEC 60904–3: 2008, ASTM G-173–03 global).

Classificationa	Effic.b (%)	Areac (cm^2)	Voc (V)	Jsc (mA/cm^2)	FFd (%)	Test Centree (and Date)	Description
a CIGS = CuInGaSe2; a-Si = amorphous silicon/hydrogen alloy. b Effic. = efficiency. c (ap) = aperture area; (t) = total area; (da) = designated illumination area. d FF = fill factor. e FhG-ISE = Fraunhofer Institut für Solare Energiesysteme; JQA = Japan Quality Assurance; AIST = Japanese National Institute of Advanced Industrial Science and Technology. f Spectral response reported in Version 36 of these tables. g Recalibrated from original measurement. h Reported on a ‘per cell’ basis. i Not measured at an external laboratory. j Spectral response reported in present version of these tables. k Light soaked at Oerlikon prior to testing at NREL (1000 h, 1 sun, 50°C). l Measured under IEC 60904–3 Ed. 1: 1989 reference spectrum. m Stability not investigated. References 32 and 33 review the stability of similar devices. n Stabilised by 1000 h, 1 sun illumination at a sample temperature of 50°C. o Stabilised by 174 h, 1 sun illumination after 20 h, 5 sun illumination at a sample temperature of 50°C.
Silicon
Si (crystalline)	25.0 ± 0.5	4.00 (da)	0.706	42.7f	82.8	Sandia (3/99)g	UNSW PERL 17
Si (multicrystalline)	20.4 ± 0.5	1.002 (ap)	0.664	38.0	80.9	NREL (5/04)g	FhG-ISE 18
Si (thin film transfer)	16.7 ± 0.4	4.017 (ap)	0.645	33.0	78.2	FhG-ISE (7/01)g	U. Stuttgart (45 µm thick) 19
Si (thin film submodule)	10.5 ± 0.3	94.0 (ap)	0.492h	29.7h	72.1	FhG-ISE (8/07)g	CSG Solar (1–2 µm on glass; 20 cells) 20
III–V cells
GaAs (thin film)	27.6 ± 0.8	0.9989 (ap)	1.107	29.6j	84.1	NREL (11/10)	Alta Devices4
GaAs (multicrystalline)	18.4 ± 0.5	4.011 (t)	0.994	23.2	79.7	NREL (11/95)g	RTI, Ge substrate 21
InP (crystalline)	22.1 ± 0.7	4.02 (t)	0.878	29.5	85.4	NREL (4/90)g	Spire, epitaxial 22
Thin Film Chalcogenide
CIGS (cell)	19.6 ± 0.6i	0.996 (ap)	0.713	34.8j	79.2	NREL (4/09)	NREL, CIGS on glass5, 23
CIGS (submodule)	16.7 ± 0.4	16.0 (ap)	0.661h	33.6h	75.1	FhG-ISE (3/00)g	U. Uppsala, 4 serial cells 24
CdTe (cell)	16.7 ± 0.5h	1.032 (ap)	0.845	26.1	75.5	NREL (9/01)g	NREL, mesa on glass 25
CdTe (submodule)	12.5 ± 0.4	35.03 (ap)	0.838	21.2j	70.5	NREL (9/10)	ASP Hangzhou, 8 serial cells
Amorphous/nanocrystalline Si
Si (amorphous)	10.1 ± 0.3k	1.036 (ap)	0.886	16.75f	67	NREL (7/09)	Oerlikon Solar Lab, Neuchatel 26
Si (nanocrystalline)	10.1 ± 0.2l	1.199 (ap)	0.539	24.4	76.6	JQA (12/97)	Kaneka (2 µm on glass) 27
Photochemical
Dye sensitised	10.4 ± 0.3m	1.004(ap)	0.729	22	65.2	AIST (8/05)g	Sharp 28
Dye sensitized (submodule)	9.9 ± 0.4m	17.11 (ap)	0.719h	19.4h^,j	71.4	AIST (8/10)	Sony, 8 parallel cells6
Organic
Organic polymer	8.3 ± 0.3m	1.031 (ap)	0.816	14.46j	70.2	NREL(11/10)	Konarka7
Organic (submodule)	3.5 ± 0.3m	208.4 (ap)	8.62	0.847	48.3	NREL (7/09)	Solarmer 29
Multijunction devices
GaInP/GaAs/Ge	32.0 ± 1.5l	3.989 (t)	2.622	14.37	85	NREL (1/03)	Spectrolab (monolithic)
GaAs/CIS (thin film)	25.8 ± 1.3l	4.00 (t)	—	—	—	NREL (11/89)	Kopin/Boeing (4 terminal) 30
a-Si/µc-Si (thin film cell)	11.9 ± 0.8n	1.227	1.346	12.92j	68.5	NREL (8/10)	Oerlikon Solar Lab, Neuchatel8
a-Si/µc-Si (thin film submodule)j^,l	11.7 ± 0.4l^,o	14.23 (ap)	5.462	2.99	71.3	AIST (9/04)	Kaneka (thin film) 31
Organic (2-cell tandem)	8.3 ± 0.3m	1.087 (ap)	1.733	8.03j	59.5	FhG-ISE (10/10)	Heliatek9

Table II. Confirmed terrestrial module efficiencies measured under the global AM1.5 spectrum (1000 W/m2) at a cell temperature of 25°C (IEC 60904–3: 2008, ASTM G-173–03 global).

Classificationa	Effic.b (%)	Areac (cm^2)	Voc (V)	Isc (A)	FFd (%)	Test centre (and date)	Description
a CIGSS = CuInGaSSe; a-Si = amorphous silicon/hydrogen alloy; a-SiGe = amorphous silicon/germanium/hydrogen alloy. b Effic. = efficiency. c (ap) = aperture area; (da) = designated illumination area. d FF = fill factor. e Recalibrated from original measurement. f Spectral response reported in present version of these tables. g Lightsoaked at NREL for 1000 h at 50°C, nominally 1-sun illumination. h Measured under IEC 60904–3 Ed. 1: 1989 reference spectrum.
Si (crystalline)	22.9 ± 0.6	778 (da)	5.6	3.97	80.3	Sandia (9/96)e	UNSW/Gochermann 34
Si (large crystalline)	21.4 ± 0.6	15780 (ap)	68.6	6.293	78.4	NREL (10/09)	SunPower 35
Si (multicrystalline)	17.55 ± 0.5	14701 (ap)	38.31	8.94f	75.3	ESTI (8/10)	Schott Solar (60 serial cells)10
Si (thin-film polycrystalline)	8.2 ± 0.2	661(ap)	25	0.32	68	Sandia (7/02)e	Pacific Solar (1–2 µm on glass) 36
CIGS	15.7 ± 0.5	9703 (ap)	28.24	7.254f	72.5	NREL (11/10)	Miasole11
CIGSS (Cd free)	13.5 ± 0.7	3459 (ap)	31.2	2.18	68.9	NREL (8/02)e	Showa Shell 37
CdTe	10.9 ± 0.5	4874 (ap)	26.21	3.24	62.3	NREL (4/00)e	BP Solarex 38
a-Si/a-SiGe/a-SiGe (tandem)	10.4 ± 0.5g^,h	905 (ap)	4.353	3.285	66	NREL (10/98)e	USSC 39

Table III. ‘Notable Exceptions’: ‘Top ten’ confirmed cell and module results, not class records measured under the global AM1.5 spectrum (1000 Wm⁻²) at 25°C (IEC 60904–3: 2008, ASTM G-173–03 global).

Classificationa	Effic.b (%)	Areac (cm^2)	Voc (V)	Jsc (mA/cm^2)	FF (%)	Test centre (and date)	Description
a CIGS = CuInGaSe2. b Effic. = efficiency. c (ap)= aperture area; (t) = total area; (da) = designated illumination area. d Recalibrated from original measurement. e Spectral response reported in present version of these tables. f Spectral response reported in Version 36 of these tables. g Light soaked under 100mW/cm^2 white light at 50°C for 1000 h. h Stability not investigated.
Cells (silicon)
Si (MCZ crystalline)	24.7 ± 0.5	4.0 (da)	0.704	42	83.5	Sandia (7/99)d	UNSW PERL, SEH MCZ substrate 40
Si (large crystalline)	24.2 ± 0.7	155.1(t)	0.721	40.5e	82.9	NREL (5/10)	Sunpower n-type CZ substrate12
Si (large crystalline)	23.0 ± 0.6	100.4(t)	0.729	39.6	80	AIST (2/09)	Sanyo HIT, n-type substrate 41
Si (large multicrystalline)	19.3 ± 0.5	217.7(t)	0.651	38.8f	76.4	AIST (7/09)	Mitsubishi Electric honeycomb 42
Cells (other)
GaInP/GaAs/GaInAs (tandem)	35.8 ± 1.5	0.880 (ap)	3.012	13.9	85.3	AIST (9/09)	Sharp, monolithic 43
CIGS (thin film)	20.3 ± 0.6	0.5015 (ap)	0.740	35.4e	77.5	FhG-ISE (6/10)	ZSW Stuttgart, CIGS on glass13
a-Si/nc-Si/nc-Si (tandem)	12.5 ± 0.7 g	0.27 (da)	2.01	9.11	68.4	NREL (3/09)	United Solar stabilised 44
Dye-sensitised	11.2 ± 0.3h	0.219 (ap)	0.736	21	72.2	AIST (3/06)d	Sharp 45
Luminescent submodule	7.1 ± 0.2h	25(ap)	1.008	8.84	79.5	ESTI (9/08)	ECN Petten, GaAs cells14

To ensure discrimination, Table III is limited to nominally 10 entries with the present authors having voted for their preferences for inclusion. Readers who have suggestions of results for inclusion into this table are welcome to contact any of the authors with full details. Suggestions conforming to the guidelines will be included on the voting list for a future issue.

Table IV shows the best results for concentrator cells and concentrator modules (a smaller number of ‘notable exceptions’ for concentrator cells and modules additionally is included in Table IV).

Table IV. Terrestrial concentrator cell and module efficiencies measured under the ASTM G-173–03 direct beam AM1.5 spectrum at a cell temperature of 25°C.

Classification	Effic.a (%)	Areab (cm^2)	Intensityc (suns)	Test centre (and date)	Description
a Effic. = efficiency. b (da) = designated illumination area; (ap) = aperture area. c One sun corresponds to direct irradiance of 1000 W/m. d Not measured at an external laboratory. e Spectral response reported in Version 36 of these tables. f Measured under a low aerosol optical depth spectrum similar to ASTM G-173–03 direct52. g Measured under old ASTM E891–87 reference spectrum. h Recalibrated from original measurement. i Spectral response reported in the present version of these tables.
Single cells
GaAs	29.1 ± 1.3d^,e	0.0505 (da)	117	FhG-ISE (3/10)	Fraunhofer ISE
Si	27.6 ± 1.0f	1.00 (da)	92	FhG-ISE (11/04)	Amonix back-contact 46
Multijunction cells
InGaP/GaAs/InGaAs (2-terminal)	42.3 ± 2.5i	0.9756 (ap)	406	NREL (9/10)	Spire, bi-facial epigrowth15
GaInP/GaInAs/Ge (2-terminal)	41.6 ± 2.5e	0.3174(da)	364	NREL (8/09)	Spectrolab, lattice-matched 47
Submodules
GaInP/GaAs; GaInAsP/GaInAs	38.5 ± 1.9i	0.202 (ap)	20	NREL (8/08)	DuPont et al., split spectrum16
GaInP/GaAs/Ge	27.0 ± 1.5g	34 (ap)	10	NREL (5/00)	ENTECH 48
Modules
Si	20.5 ± 0.8d	1875 (ap)	79	Sandia (4/89)h	Sandia/UNSW/ENTECH (12 cells) 49
Notable exceptions
GaInP/GaAs (2-terminal)	32.6 ± 2.0e	0.010 (da)	1026	FhG-ISE (9/08)	U. Polytecnica de Madrid 50
Si (large area)	21.7 ± 0.7	20.0 (da)	11	Sandia (9/90)h	UNSW laser grooved 51

Fourteen new results are reported in the present version of these Tables.

The first new result in Table I is an outright record for solar conversion by any single-junction photovoltaic device. An efficiency of 27.6% has been measured at the National Renewable Energy Laboratory (NREL) for a 1 cm² thin-film GaAs device fabricated by Alta Devices, Inc.. Alta Devices is a Santa Clara based “start-up” seeking to develop low-cost, 30% efficient solar modules 4.

The second new result in Table I is an efficiency improvement to 19.6% for a 1 cm² single-junction copper–indium–gallium–selenide (CIGS) cell fabricated by and measured at NREL 5. Although CIGS efficiency of 20% and higher has been reported previously by two groups (see Table III), this has been for cells appreciably less than 1 cm² in area, the minimum considered reasonable for efficiency comparisons in these Tables and for milestones in most of the international programs.

A third new result in Table I is 12.5% efficiency for an eight cell 35 cm² CdTe submodule fabricated by Advanced Solar Power (ASP) Hangzhou, also measured by NREL.

A fourth new result in Table I is for a dye sensitized submodule with efficiency of 9.9% reported for a 17 cm² submodule fabricated by Sony 6 and measured by the Japanese National Institute of Advanced Industrial Science and Technology (AIST). This is quite close to the record of 10.4% efficiency for the best individual dye sensitised cell yet confirmed (of more that 1 cm² area).

Another outstanding new result is the measurement of 8.3% efficiency at NREL for a 1cm² organic cell fabricated by Konarka 7, representing a massive improvement over the company's previous 5.15% record entry. An intermediate result of 6.5% was measured in July 2010.

Another new result in Table I is for a double-junction amorphous/microcrystalline silicon cell with stabilized efficiency of 11.9% reported for a 1.2 cm² cell fabricated by Oerlikon and Corning 8 and again measured by NREL, after stabilization.

The final new result in Table I is for a double-junction organic solar cell with 8.3% efficiency measured for a 1.1 cm² cell fabricated by Heliatek 9 and measured by the Fraunhofer Institute for Solar Energy Systems (FhG-ISE). This represents rapid progress from the 6.1% result from Heliatek measured in June last year and reported in the previous version of these Tables. An intermediate result of 7.7% was measured in March 2010.

Following a similarly vigorous burst of activity in the multicrystalline silicon module area reported in the two previous versions of these Tables, where four groups exceeded the previous record for module efficiency over the two reporting periods, a fifth group has done even better. In Table II, a new efficiency record of 17.55% is reported for a large (1.5 m² aperture area) module fabricated by Schott Solar 10 and measured by the European Solar Test Installation, Ispra (ESTI).

Also reported in Table II is a record result for a thin-film module, with a large improvement to 15.7% reported for a 1 m² CIGS module fabricated by Miasole 11 and measured by NREL.

The first new result in Table III relates to an efficiency increase to 24.2% for a large 155 cm² silicon cell fabricated on an n-type Czochralski grown wafer, with the cell fabricated by SunPower 12 and also measured by NREL.

Another new result in Table III is the further improvement of a small area (0.5 cm²) CIGS cell fabricated by Zentrum für Sonnenenergie- und Wasserstoff- Forschung (ZSW), Stuttgart 13 to 20.3% efficiency as measured by FhG-ISE. This cell is smaller than the 1 cm² size required for classification as an outright record, as previously discussed.

The final new result in Table III is for a luminescent concentrating submodule using high performance GaAs cells placed along the edge of a luminescent plate to convert the collected luminescent radiation. An efficiency of 7.1% was confirmed for a 25 cm² test device fabricated by ECN, Netherlands 14 and measured by ESTI.

Two more new results are reported in Table IV for more conventional concentrator cells and systems. The first is a new efficiency record for any photovoltaic cell with 42.3% efficiency measured by NREL at 406 suns concentration (irradiance) for a 1 cm² cell fabricated by the Spire Corporation 15. A new approach was used whereby a low bandgap InGaAs cell was grown on one side of a GaAs wafer, with the wafer then flipped over and an intermediate bandgap GaAs followed by a high bandgap InGaP cell grown on the other side.

The final new result represents a new record for the conversion of sunlight to electricity by any means. An efficiency of 38.5% was measured by NREL for a very small area (0.2 cm²) spectral-splitting submodule at about 20 suns concentration as the result of a multi-institutional effort headed by DuPont 16. This complete lens/cell assembly uses a dichroic reflector to steer light to two different two-cell stacks, one on a GaAs substrate and one on an InP substrate.

The external quantum efficiencies (EQE) normalized to the peak EQE values for the new organic cell results of Table I are shown in Figure 1(a) as well as the response for the GaAs cell and CdTe and dye-sensitised submodules of Table I. Also shown is the decomposition into the top and bottom cell response for the 8.3% Heliatek tandem cell of Table I. Interestingly, both cells in the stack have largely overlapping spectral response range, although complementary in some aspects.

Figure 1. (a) Normalised external quantum efficiency (EQE) for the new organic and GaAs cell results in this issue and for the new CdTe and dye-sensitised submodule results; (b) Normalised EQE for the three new CIGS cell and module entries in this issue plus for the three new silicon cell and module results; (c) EQE of the composite cells for the new concentrator cell and submodule entries in the present issue.

Figure 1(b) shows the normalized EQE of the new CIGS and silicon results in the present issue of these tables. Quite striking is the almost identical responses of the NREL and ZSW CIGS cells with the higher current from the ZSW cell attributed to a slightly lower bandgap edge. The normalized responses of both cells in the Oerliken/Corning micromorph tandem cell are also shown.

Figure 1(c) shows the absolute EQE for the different cells contributing to the new concentrator cell and submodule results of Table IV. The much narrower response bandwidth of the bottom InGaAs cell in the 42.3% Spire monolithic stack compared to the response of the bottom Ge in the 41.6% Spectrolab device 3 reflects a higher bandgap. This gives a higher voltage output that contributes to the improved performance. The EQE for the 38.5% submodule differs slightly from results reported elsewhere 16 due to incorporation of the effect of the dichroic reflector used in this system. Each of the four cells in this system is contacted separately, removing the need for current matching.

DISCLAIMER

While the information provided in the tables is provided in good faith, the authors, editors and publishers cannot accept direct responsibility for any errors or omissions.